Twenty-seven people were killed and 31 seriously injured when their bus plunged into a ravine in northern Ethiopia, police said on Saturday. "A public bus on its way to Addis Ababa from Gojjam in northern Ethiopia fell into a 50 meter (160 foot) deep ravine killing 26 passengers at around midday Thursday," a police statement said. A police spokesman in Amhara region said another passenger had died in hospital, bringing the death toll to 27. He said the cause of the crash was being investigated. The Alem Transportation Company bus veered off the road at Adet, 250 km (155 miles) north of the capital Addis Ababa, police said, adding that the injured had been taken to hospital in Bahr Dar, capital of Amhara region.